Peregrines don't make a nest like many birds. They simply make a scrape in whatever material there is.
To this end, I put some gravel (actually smooth sided shingle from a local garden centre) in the tray.
Last year's spent gravel was removed some months ago, but I haven't replenished it as we were hoping to replace this old wooden tray. Unfortunately due to circumstances beyond my control, the new tray will have to wait for another year.
Here is the male Christopher Robin (CR) wondering where the gravel has gone!
Don't worry, it will all be back in a few days!